The joint angle is set by aligning the guide to the “X” brace layout. I set a piece of 1 by 2 on one brace outline so the tool can be butted against something solid. Once set the wing nut gets tightened. Since the angles are complimentary you only need to do this once.

The tool allows you to line up your cut mark and secure the brace with a small clamp. The razor saw is accurately positioned along the angle gage, which aids keeping the blade perpendicular.

The tool is made of ¼ inch ply. Each leg is about 2X10 inches. The lower leg has two risers epoxied to the edges they need to be about 11/16” tall.

The photo of the bottom of the lower leg reveals the two cross stabilizers. You can also see that the ¼” carriage bolt is glued in place.

The upper leg has two pieces of ¼ “ material glued along the edge to act as a stabilizer for the razor saw.

A riser 11/16” tall needs to be glued to the bottom of the upper leg to keep the whole unit level with the work surface.

TOP VIEW

BOTTOM VIEW

None of the dimensions are critical, the idea is to be able to move and clamp the braces along the bottom leg using the upper leg to pin point the cut location. Note that I am left handed --- so perhaps some would find the fixture easier to use if it were reversed? In any event I am now able to go from layout to layout and cut perfect squeaky tight “X” brace lap joints in a minute or two.